Method for manufacturing minute structure, method for manufacturing liquid discharge head, and liquid discharge head

ABSTRACT

A method for manufacturing a minute structure comprises a step of forming an ionizing radiation decomposing type positive type resist layer including a methyl isopropenyl ketone as a first positive type photosensitive material layer, a step of forming an ionizing radiation decomposing type positive type resist layer including a photosensitive material of a copolymer as a second positive type photosensitive material layer to be sensitized by an ionizing radiation of a second wavelength range on the first positive type photosensitive material layer, a step of forming a desired pattern in the above-mentioned second positive type photosensitive material layer, and development using a developing solution, and then, a step of forming a desired pattern in the above-mentioned first positive type photosensitive material layer to form a convex shape pattern.

TECHNICAL FIELD

The present invention relates to a method for manufacturing a minutestructure using a photosensitive resin, and a liquid discharge head forgenerating recording liquid small droplets used for the ink jetrecording system and a method for manufacturing the head. In particular,the present invention relates to a method for manufacturing a headcomprising an ink liquid flow path shape, capable of stably dischargingminute liquid droplets enabling a high image quality, and furthermorecapable of realizing a high speed recording operation. Furthermore, thepresent invention relates to an ink jet head with the ink dischargeproperties improved, based on the above-mentioned method formanufacturing an ink jet head.

BACKGROUND ART

A liquid discharge head applied for the ink jet recording system (liquiddischarge recording system) for recording by discharging a recordingliquid such as an ink in general comprises a liquid flow path, a liquiddischarge energy generating part provided in a part of the liquid flowpath, and a minute recording liquid discharge port for discharging theliquid in the above-mentioned liquid flow path by the thermal energy ofthe liquid discharge energy generating part (hereinafter it is referredto as the “orifice”).

Conventionally, as a method for manufacturing such a liquid dischargerecording head, for example, Japanese Patent Application Publication No.H06-45242 discloses a method for manufacturing an ink jet head,comprising the steps of patterning a mold of an ink liquid flow pathwith a photosensitive material on a substrate with a liquid dischargeenergy generating element formed, then applying and forming a coatingresin layer on the above-mentioned substrate so as to coat the moldpattern, forming an ink discharge port communicating with the mold ofthe above-mentioned ink liquid flow path on the coating resin layer, andthereafter removing the photosensitive material used for the mold(hereinafter, it is also abbreviated as the “mold injection method”).According to the production method for a head, a positive type resist isused as the photosensitive material from the viewpoint of the removaleasiness. Moreover, according to the production method, since thesemiconductor photolithography technique is adopted, an extremely highlyaccurate and minute process is enabled for the formation of the inkliquid flow path, the discharge port, or the like. However, according tothe production method adopting the semiconductor production method,basically, the shape change in the vicinity of the ink liquid flow pathand the discharge port is limited to the change in the two-dimensionaldirection parallel to the element substrate. That is, since thephotosensitive material layer cannot be provided partially in a multiplelayers due to the use of the photosensitive material for the mold of theink liquid flow path and the discharge port, a desired pattern with thechange in the height direction cannot be obtained in the mold for theink liquid flow path, or the like (the height direction shape from theelement substrate is uniformly limited). As a result, it becomes thelimitation in the ink liquid flow path design for realizing the highspeed and stable discharge.

As a technique for solving the same, Japanese Patent ApplicationLaid-Open No. 2003-25595 proposes forming an intermediate chamber withdissolvable resins in two layers and the cross-sectional area in thedischarge port lower part that is enlarged (an intermediate portionnarrower than the substrate side liquid flow path and wider than thedischarge port top end part is provided between the substrate sideliquid flow path and the discharge port top end). Moreover, the officialgazette discloses a specific example of using a thermally cross-linkablepositive type resist including a PMMA (polymethyl methacrylate) for thelower layer of the removable two layer resins and using a PMIPK(polymethyl isopropyl ketone) for the upper layer.

On the other hand, Japanese Patent Application Laid-Open No. 2004-042396discloses a method for manufacturing an ink jet recording head using forthe liquid flow path forming mold material, a copolymer of an estermethacrylate and a methacrylic acid as a thermal cross linking factor asthe resin used for a solid layer for manufacturing a mold for formingthe liquid flow path. Furthermore, Japanese Patent Application Laid-OpenNo. 2004-42650 discloses a method for manufacturing an ink jet recordinghead using for the mold material for forming a liquid flow path, athermally cross linkable positive type resist as a copolymer of amethacrylic anhydride as a factor for widening the sensitive area,including an ester methacrylate.

By forming the mold material for forming a liquid flow path of a liquiddischarge head in a two layer laminated structure using two kinds ofpositive type resists, the flexibility in designing the minute liquidflow path structure for a liquid discharge head can be widened. However,for providing a further minute liquid discharge head structure, atechnique for forming a minute structure further accurately is calledfor. For example, in some cases the lower layer of the mold material forthe liquid flow path comprising the two-layer structure may need to bethick to some extent. In this case, if the positive type resist forforming the lower layer of the mold material for the two layer structureliquid flow path is thermally cross linkable type as disclosed inJapanese Patent Application Laid-Open Nos. 2003-25595, 2004-042396 and2004-42650, there would be many limitations in terms of the design andthe production method, such as:

-   1. the difficulty in providing a thick film due to the film stress    limitation (maximum: 10 μm is the limit);-   2. generation of cracking at the time of forming a pattern (cracking    in the bent pattern derived from the stress alleviation at the time    of the development);-   3. generation of cracking, or the like due to application shock    derived from the grade difference on the substrate by applying a    coating solution including a solvent onto a thermally cross linkable    film;-   4. increase of the necessary exposure amount at the time of    patterning due to reduction of the decomposition rate by the    exposure by the mesh like three-dimensional structure at the time of    the thermally cross linkable film formation; and-   5. increase of the exposure amount for decomposition at the time of    finally removing the mold material.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a method for forming aminute structure without the need of the thermal cross linking process(high temperature process) in at least the lower layer in the case ofproduction of the above-mentioned minute structure of the two layerstructure with two kinds of positive type resists, without generation ofthe above-mentioned problems. Furthermore, an object of the presentinvention is to provide a method for manufacturing a liquid dischargehead, utilizing the method for forming a minute structure.

The present invention capable of achieving the above-mentioned objectsis characterized in first realizing a production method for forming athree-dimensionally shaped liquid flow path by high accuracy, and thenfinding out a good liquid flow path shape to be realized by theproduction method. Furthermore, the present invention is characterizedin forming the above-mentioned three-dimensionally shaped liquid flowpath highly accurately and inexpensively with a good yield.

Moreover, it is to provide an ink jet recording head compatible tovarious kinds of inks by widening the design flexibility of thethree-dimensionally shaped flow path structure to be formed.

That is, the first invention is a method for manufacturing a minutestructure, comprising:

a step of forming an ionizing radiation decomposing type positive typeresist layer including a methyl isopropenyl ketone as a first positivetype photosensitive material layer to be sensitized by an ionizingradiation (Deep-UV, electron beam, X ray, or the like) of a firstwavelength range;

a step of forming an ionizing radiation decomposing type positive typeresist layer including a photosensitive material of a copolymer obtainedby the copolymerization of an ester methacrylate and a methacrylic acid,with the weight average molecular weight of the copolymer of 50,000 to300,000 and the ratio of the methacrylic acid included in the copolymerof 5 to 30% by weight as a second positive type photosensitive materiallayer to be sensitized by an ionizing radiation of a second wavelengthrange on the first positive type photosensitive material layer;

a step of forming a desired pattern in the above-mentioned secondpositive type photosensitive material layer as the upper layer bydecomposing reaction only in the desired area of the above-mentionedsecond positive type photosensitive material layer without decomposingreaction of the above-mentioned first positive type photosensitivematerial layer by directing an ionizing radiation of the above-mentionedsecond wavelength range via a mask to the substrate surface with thefirst and second positive type photosensitive material layers formed,and development using a developing solution; and

a step of forming a desired pattern in the above-mentioned firstpositive type photosensitive material layer as the lower layer bydecomposing reaction of a predetermined area of at least theabove-mentioned first positive type photosensitive material layer bydirection an ionizing radiation of the above-mentioned first wavelengthrange via a mask to the substrate surface with the first and secondpositive type photosensitive material layers formed, and development,successively,

characterized in that a pattern of a convex shape is manufactured in thesubstrate by executing the above-mentioned steps.

The second invention is characterized in that an ionizing radiationdecomposing type positive type resist including a photosensitivematerial as a copolymer obtained by the copolymerization of an estermethacrylate and a methacrylic anhydride, with the weight averagemolecular weight of the copolymer of 10,000 to 100,000 and the ratio ofthe methacrylic anhydride included in the copolymer of 5 to 30% byweight is used as the above-mentioned second positive typephotosensitive material layer in the first invention.

The third invention is a method for manufacturing a liquid dischargehead comprising a step of forming a mold pattern with a removable resinin a liquid flow path forming portion on a substrate with a liquiddischarge energy generating element formed, applying and hardening acoating resin layer on the above-mentioned substrate so as to coat themold pattern, and dissolving and removing the above-mentioned moldpattern so as to form a liquid flow path, characterized in that theabove-mentioned step of forming a mold pattern comprises:

a step of forming an ionizing radiation decomposing type positive typeresist layer including a methyl isopropenyl ketone as the first positivetype photosensitive material layer to be sensitized by an ionizingradiation beam of the first wavelength range on the substrate;

a step of forming an ionizing radiation decomposing type positive typeresist layer including a photosensitive material of a copolymer obtainedby the copolymerization of an ester methacrylate and a methacrylic acid,with the weight average molecular weight of the copolymer of 50,000 to300,000 and the ratio of the methacrylic acid included in the copolymerof 5 to 30% by weight as a second positive type photosensitive materiallayer to be sensitized by an ionizing radiation of a second wavelengthrange on the first positive type photosensitive material layer;

a step of forming a desired pattern in the above-mentioned secondpositive type photosensitive material layer as the upper layer bydecomposing reaction only in the desired area of the above-mentionedsecond positive type photosensitive material layer without decomposingreaction of the above-mentioned first positive type photosensitivematerial layer by directing an ionizing radiation of the above-mentionedsecond wavelength range via a mask to the substrate surface with thefirst and second positive type photosensitive material layers formed,and development using a developing solution; and

a step of forming a desired pattern in the above-mentioned firstpositive type photosensitive material layer as the lower layer bydecomposing reaction of a predetermined area of at least theabove-mentioned first positive type photosensitive material layer bydirection an ionizing radiation of the above-mentioned first wavelengthrange via a mask to the substrate surface with the first and secondpositive type photosensitive material layers formed, and development,successively.

The fourth invention is characterized in that an ionizing radiationdecomposing type positive type resist including a photosensitivematerial as a copolymer obtained by the copolymerization of an estermethacrylate and a methacrylic anhydride, with the weight averagemolecular weight of the copolymer of 10,000 to 100,000 and the ratio ofthe methacrylic anhydride included in the copolymer of 5 to 30% byweight is used as the above-mentioned second positive typephotosensitive material layer in the third invention.

The fifth invention is a method for manufacturing a liquid dischargehead comprising a step of forming a mold pattern with a removable resinin a liquid flow path forming portion on a substrate with a liquiddischarge energy generating element formed, applying and hardening acoating resin layer on the above-mentioned substrate so as to coat themold pattern, and dissolving and removing the above-mentioned moldpattern in the method for manufacturing a liquid discharge head so as toform a liquid flow path, characterized in comprising at least:

a step of forming an ionizing radiation decomposing type positive typeresist layer including a methyl isopropenyl ketone as the first positivetype photosensitive material layer to be sensitized by an ionizingradiation beam of the first wavelength range on the substrate;

a step of forming an ionizing radiation decomposing type positive typeresist layer including a photosensitive material of a copolymer obtainedby the copolymerization of an ester methacrylate and a methacrylic acid,with the weight average molecular weight of the copolymer of 50,000 to300,000 and the ratio of the methacrylic acid included in the copolymerof 5 to 30% by weight as a second positive type photosensitive materiallayer to be sensitized by an ionizing radiation of a second wavelengthrange on the first positive type photosensitive material layer;

a step of forming a desired pattern in the above-mentioned secondpositive type photosensitive material layer as the upper layer bydecomposing reaction only in the desired area of the above-mentionedsecond positive type photosensitive material layer without decomposingreaction of the above-mentioned first positive type photosensitivematerial layer by directing an ionizing radiation of the above-mentionedsecond wavelength range via a mask to the substrate surface with thefirst and second positive type photosensitive material layers formed,and development using a developing solution;

a step of forming a desired pattern in the above-mentioned firstpositive type photosensitive material layer as the lower layer bydecomposing reaction of a predetermined area of at least theabove-mentioned first positive type photosensitive material layer bydirection an ionizing radiation of the above-mentioned first wavelengthrange via a mask to the substrate surface with the first and secondpositive type photosensitive material layers formed, and development;

a step of forming a pattern including the discharge port by applying aphotosensitive coating resin film onto the first and second positivetype photosensitive material layers with the above-mentioned desiredpattern formed, exposing a pattern including a discharge openingcommunicating with the above-mentioned liquid flow path, anddevelopment;

a step of decomposing the resin components in the pattern comprising theabove-mentioned first and second positive type photosensitive materiallayers by directing an ionizing radiation beam of a wavelength range forthe decomposing reaction of both the above-mentioned first and secondpositive type photosensitive material layers via the above-mentionedphotosensitive coating resin film; and

a step of soaking the substrate after having the above-mentioned stepsin a predetermined organic solvent for dissolving and removing thepattern comprising the above-mentioned first and second positive typephotosensitive material layers.

The sixth invention is characterized in that an ionizing radiationdecomposing type positive type resist including a photosensitivematerial as a copolymer obtained by the copolymerization of an estermethacrylate and a methacrylic anhydride, with the weight averagemolecular weight of the copolymer of 10,000 to 100,000 and the ratio ofthe methacrylic anhydride included in the copolymer of 5 to 30% byweight is used as the above-mentioned second positive typephotosensitive material layer in the fifth invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B, 1C, 1D, 1E and 1F are explanatory diagrams each forexplaining a basic process flow of a production method of the presentinvention.

FIGS. 2A, 2B, 2C, 2D, 2E, 2F, 2G and 2H are diagrams showing a processfor manufacturing an ink jet head including the processes of FIGS. 1A to1F.

FIG. 3 is a schematic diagram of an optical system of a commonly usedexposing device.

FIGS. 4A, 4B, 4C 4D, 4E, 4F and 4G are diagrams each showing a processflow in the case of using a methacrylate based resist for the upperlayer in a production method of the present invention.

FIGS. 5A, 5B, 5C and 5D are diagrams each showing the subsequent stepsof the processes of FIGS. 4A to 4G.

FIG. 6A is a vertical cross-sectional view showing the nozzle structureof an ink jet head with the discharge chamber improved by the productionmethod of the present invention, and FIG. 6B is a verticalcross-sectional view showing the nozzle structure for the comparisonwith the head shown in FIG. 6A.

FIGS. 7A, 7B, 7C, 7D, 7E, 7F, 7G and 7H are schematic perspective viewseach for explaining a production method according to an embodiment ofthe present invention, and FIG. 7I is a schematic cross-sectional viewof a liquid discharge head completed by the production method shown inFIGS. 7A to 7H.

FIG. 8 is a schematic perspective view showing an ink jet head unit withthe ink discharge element obtained by the production method shown inFIGS. 7A to 7H mounted.

FIGS. 9A and 9B are diagrams each showing the nozzle structures of headsmanufactured for the comparison of the discharge properties of theproduction method of the present invention and the conventionalproduction method.

FIG. 10 is a diagram for schematically explaining the optimization ofthe nozzle shape design.

FIG. 11 is a diagram for schematically explaining the optimization ofthe nozzle shape design.

FIG. 12 is a diagram for schematically explaining the optimization ofthe nozzle shape design.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, a liquid discharge head of the present invention willbe explained with an example of an ink jet head (IJ head) for recordingusing mainly ink. The liquid discharge head of the present invention maybe of a type used for the applications other than recording, for usingvarious kinds of liquids on various kinds of surfaces. In thespecification, the ionizing radiation is a general term for theradiations capable of generating the ionizing function to a substance,such as the deep-UV beam, an electron beam, and a X-ray).

First, for easily understanding of the present invention, theoptimization in the nozzle shape design in the liquid discharge headwill be explained schematically with reference to FIGS. 10 to 12.

FIG. 10 shows a nozzle cross-sectional view of an ink jet print head 200with the configuration of the present invention provided. As to thenozzle filter disposed at a position close to the ink supply port sidein an ink flow path (nozzle) disclosed in FIG. 10, it is effective tohave the same in the configuration of the present invention in terms ofthe dust no discharge countermeasure, or the like, however, it may notbe provided terms of the effects of the present invention. The ink jetprint head having the configuration disclosed in FIG. 10 is an ink jetprint head having the configuration with a partition wall (not shown)for forming an individual ink flow path 140 per each discharge port fora plurality of heaters 160 and discharge ports 150, elongating to thevicinity of an ink supply port (not shown). The heaters 160 are formedon a substrate 130.

These ink jet print heads have an ink droplet discharge meanscharacterized in the ink jet recording method disclosed in JapanesePatent Application Laid-Open Nos. H04-10940 and H04-10941, that is,characterized in the communication of bubble generation at the time ofdischarge with the external atmosphere.

Here, the concept of the optimization of the ink jet print head capableof realizing the high-density arrangement will be explained briefly. Asthe physical amount that influences the discharge properties of the inkjet print head, the inertance (inertia force) and the resistance(viscosity resistance) in the above-mentioned nozzles arranged in aplurality contribute significantly thereto. The equation of motion of anincompressible fluid moving in an optional shape can be represented bythe following two equations.Δ·v−0 (Equation of Continuity)  1(∂v/∂t)+(v·Δ)v=−Δ(P/ρ)+(μ/ρ)Δ² v+f (Navier-Stokes Equation)  2

The above-mentioned two equations (1, 2) can be approximated withsufficiently small convection term and viscosity term without anexternal force:Δ² P=0  3So that the pressure can be represented using a harmonic function.

Then, in the case of an ink jet print head, it is described as a threeport model as shown in FIG. 11, and it can be expressed by an equivalentcircuit as shown in FIG. 12. The inertance is defined as the movingdifficulty at the time of suddenly starting movement of a static fluid.From the viewpoint of the electricity, it functions like the inductanceL that inhibits the electric current change. In the mechanical springmass model, it corresponds to the mass (weight).

The inertance can be represented by a formula as the second timedifferentiation of the fluid volume V at the time a pressure differenceis applied to the port, that is, the ratio of the flow rate F(=ΔV/Δt)with respect to the time differentiation.(Δ² V/Δt ²)=(ΔF/Δt)=(1/A)×P  4

Here, A is defined as. the inertance.

For example, with the assumption of a pipe type tube flow path having adensity ρ, a length L and a cross-sectional area S0 for simulation, theinertance A0 of the pseudo one-dimensional tube flow path can berepresented by:A0=ρ×L/S0It is leaned that it is proportional to the length of the first power ofthe flow path and inversely proportional to the first power of thecross-sectional area.

Based on the equivalent circuit shown in FIG. 12, the dischargeproperties of the ink jet print head can be predicted and analyzed as amodel.

According to the ink jet print head of the present invention, it isfound that the discharge phenomenon is the phenomenon of the transitionfrom the inertial flow to the viscous flow. In particular, according tothe bubbling initial stage in the heater portion, the inertial flow isthe mainstream, and on the contrary, according to the discharge latestage (that is, the time from the meniscus withdrawal to the return ofthe ink to the discharge port surface by the capillary tube phenomenon),the viscous flow is the mainstream. At the time, according to theabove-mentioned relational equation, at the bubbling initial stage, bythe inertance amount relationship, contribution to the dischargeproperties, in particular, the discharge volume and the discharge ratebecomes significant, and at the discharge late stage (that is, the timefrom the meniscus withdrawal to the return of the ink to the dischargeport surface by the capillary tube phenomenon), contribution to theresistance (viscosity resistance) amount, the discharge properties, inparticular, the ink refill time becomes significant.

Here, the resistance (viscosity resistance) can be described by theformula 1, and a steady stokes flow to be:ΔP=ηΔ ²μ  5So that the viscosity resistance: B can be found. Moreover, at thedischarge late stage, according to the model shown in FIG. 19, since themeniscus is formed in the vicinity of the discharge port so as togenerate the ink flow by the force mainly by the capillary tube force,it can be approximated by a two port model (one-dimensional flow model).

That is, it can be calculated by the Poiseuille's equation 6 describingthe viscous fluid.(ΔV/Δt)=(1/G)×(1/η)((ΔP/Δx)×S(x)  6

Here, G: shape factor. Moreover, since the viscosity resistance: B isderived from a fluid flowing according to an optional pressuredifference, it can be calculated by:B=S ₀ ^(L){(G×η)/S(x)}Δx  7

From the above-mentioned formula 7, with the assumption of a pipe typetube flow path having a density ρ, a length L and a cross-sectional areaS0, the resistance (viscosity resistance) is:B=8η×L/(π×S0²)So that it is leaned that it is approximately proportional to the nozzlelength of the first power of the flow path and inversely proportional tothe second power of the cross-sectional area.

Accordingly, in order to improve the discharge properties of the ink jetprint head, in particular, all of the discharge rate, the dischargevolume and the refill time, in terms of the above-mentioned inertance,it is the necessary and sufficient condition that the inertance amountform the heater to the discharge port side is made larger as much aspossible compared with the inertance amount from the heater to thesupply port side as well as the resistance (viscosity resistance) in thenozzle is made smaller.

According to the recent image quality competition of the IJ printer, inorder to pursue the photo image quality, realization of small liquiddroplets of the ink liquid droplets is accelerated. Accompaniedtherewith, the orifice (discharge port diameter) of the IJ head fordischarging the ink liquid droplets is made smaller as well. Therefor,the ink flow resistance at the orifice portion is made larger inproportion to the second power of the orifice diameter so that the inkliquid droplets can hardly jump from the orifice surface (in thisspecification, the phenomenon is referred to as the “generated firstphenomenon”). Then, the present researchers have attempted to form asmall liquid droplet nozzle as shown in FIG. 10 in order to stably jumpthe small liquid droplets out of the conventional IJ nozzle shape.

Naturally, in order to stably jump the small liquid droplets form thedischarge port surface as the cross-sectional view of the IJ nozzleshown in FIG. 10, it is necessary to make the discharge port diametersmaller. According to the method disclosed in the Japanese PatentApplication Laid-Open No. 2004-46217, it is known that the purpose ofmaking the inertance amount from the heater to the discharge port sidecompared with the inertance amount from the heater to the supply portside can be achieved by providing the grade difference in the lower partshape of the discharge port. However, it is revealed that theresistance: B of the entire nozzle contributes significantly as a factorof influencing the refill time out of the discharge properties of theink jet print head.

Here, in order to improve the discharge properties of the ink jet printhead, in particular, all of the discharge rate, the discharge volume andthe refill time, it is necessary to have the discharge port lower partshape as a two stage shape as shown in FIG. 10, and furthermore, to havethe flow path height thicker so as to have the above-mentionedresistance smaller. Then, in order to thicken the flow path height, itis important to form a desired pattern with a good yield by forming thefilm thickness of the lower layer side resist thickly at the time offorming the two layer resist.

According to the production of the IJ head as shown in FIG. 10 by thetow layer resist production method disclosed in the Japanese PatentApplication Laid-Open No. 2004-46217, a thermally cross linkable typepositive type resist material for carrying out the inter molecular crosslinking is adopted as the lower layer mold material. According to thethermally cross linkable type resist material, a firm film formation iscarried out by the inter molecular cross linking by applying a hightemperature process after formation of the coating film by spin coating,or the like. Therefor, even though it is not so remarkable in the caseof having a relatively thin film thickness, at the time of forming a 10μm or more film thickness, the below-mentioned problems are generated.

-   (1) Since the molecule mesh like structure is obtained by the inter    molecular cross linking of the coating film by carrying out the high    temperature process (180° C. or more), the properties as the    ionizing beam decomposing type resist become dull so that the light    irradiation amount (exposure amount) at the time of forming the    pattern is increased so as to lower the productivity.-   (2) Since the thermally cross linkable film has the molecules    coupled on the mesh, there are points whereat the decomposition by    the light irradiation can easily be generated and points whereat the    it can hardly be generated so that crack, or the like can often be    generated depending on the pattern shape.-   (3) The above-mentioned mold forming member is for completing a    nozzle for the ink jet head by the processes of applying a nozzle    forming member so as to form a discharge port, or the like, and then    removing the mold forming member via the nozzle forming member.    Therefore, it is found out that in the case a thermally cross    linkable film is adopted for the thick film mold forming material,    problems such as the light irradiation amount increase in the    above-mentioned removing process or the residue in the removing    process with a chemical liquid, or the like are generated.-   (4) As mentioned above, in a thermally cross linkable film, since    the inter molecular mesh like network formation is caused partially,    the solubility by a solvent tends to be promoted at the points    whereat the inter molecular cross linking is not sufficient. As a    result, a phenomenon of having the flow path shape in a distorted    shape can be generated.

Then, it is desired to use the mold material forming member withoutthermal cross linking, however, if the thermally cross linkable filmsdisclosed in the Japanese Patent Application Laid-Open No. 2004-46217 orthe Japanese Patent Application Laid-Open No. 2003-25595 are formed onlyby a low temperature process (less than 180° C.) without thermal crosslinking, since the network on the mesh among the molecules by the intermolecular cross linking cannot be formed, the solubility resistance withrespect to a solvent, such as a developing agent is lowered so that apattern having a purposed film thickness cannot be left.

Then, as a result of the elaborate discussion of the present inventors,a configuration of forming the nozzle for the IJ head as shown in FIG.10 accurately and inexpensively (with a good yield), capable ofcorresponding to a desired film thickness without thermally crosslinking the mold material was found out.

That is, the above-mentioned problems are solved by using a ponopolymerwith a methyl isopropenyl ketone as the main component for a positivetype photosensitive resin composition for forming a first positive typephotosensitive material layer to be the lower layer (hereinafter, it isreferred to simply as the PMIPK), and using one as a copolymer of anester methacrylate and a methacrylic acid, or a copolymer of an estermethacrylate and a methacrylic anhydride as the resin component for apositive type photosensitive resin composition for forming a secondpositive type photosensitive material layer (hereinafter, they arereferred to as the PMMA based copolymers as the general term).

The methacrylic acid/ester methacrylate copolymer used in the presentinvention is a copolymer obtained by the radical polymerization of amethacrylic acid and an ester methacrylate, including a unit (B)obtained from a methacrylic acid and a unit (A) obtained from an estermethacrylate shown below. The polymerization ratio of the unit (B) withrespect to the entire copolymer can be selected preferably from 5 to 30%by mass, and more preferably from 8 to 12% by mass.

R² in the ester methacrylate component represents an alkyl group having1 to 3 carbon atoms, and R¹ shows an alkyl group having 1 to 3 carbonatoms. Moreover, R³ in the methacrylic acid component shows an alkylgroup having 1 to 3 carbon atoms. Moreover, R¹ to R³ have theabove-mentioned meanings independently per each unit. That is, a largenumber of the units (A) may have the same R¹ or the same R², or a largenumber of the units (A) may include the combinations having at least oneof R¹ and R² differently. The same is applied to the unit (B). Thecopolymer comprises the above-mentioned (A) and (B) units, and itspolymerization form is not particularly limited as long as theproperties of a desired positive type resist can be obtained by therandom copolymerization, the block copolymerization, or the like.Furthermore, it is preferable that the copolymer has a 50,000 to 300,000molecular weight (weight average), and the dispersity (Mw/Mn) in a rangeof 1.2 to 4.0.

The absorbing wavelength range for decomposition of the resin componentof the photosensitive resin composition is preferably only 200 to 250nm. Moreover, for the development after the light irradiation, asolution mixture of a diethylene glycol, a morpholin, a monoethanolamine and pure water, or the like can be used.

On the other hand, the methacrylic anhydride/ester methacrylatecopolymer used in the present invention is a copolymer obtained by thecopolymerization of a methacrylic anhydride and an ester methacrylateshown below.

The weight ratio of the methacrylic anhydride in the copolymer withrespect to the total amount of the methacrylic anhydride and the estermethacrylate can be selected preferably from 3 to 30% by mass, and morepreferably from 8 to 12% by mass.

R² in the ester methacrylate component represents an alkyl group having1 to 3 carbon atoms, and R¹ shows an alkyl group having 1 to 3 carbonatoms. Moreover, R¹ to R² have the above-mentioned meaningsindependently per each unit. That is, at least one kind of the estermethacrylates represented by the above-mentioned formulae can becopolymerized with a methacrylic anhydride. The copolymer can beobtained form the above-mentioned monomer components, and itspolymerization form is not particularly limited as long as theproperties of a desired positive type resist can be obtained by therandom copolymerization, the block copolymerization, or the like.Therefore, the copolymer has the structure units shown by the followinggeneral formulae 1 and 2:

(In the general formulae 1 and 2, R³ to R⁶ show each independently ahydrogen atom, or an alkyl group having 1 to 3 carbon atoms. Moreover,R³ to R⁶ have the above-mentioned meaning independently per each unit.)

Furthermore, as the copolymer, those having a 10,000 to 100,000molecular weight (weight average), and the dispersity (Mw/Mn) in a rangeof 1.2 to 5.0 are preferable.

The absorbing wavelength range for decomposition of the resin componentof the photosensitive resin composition is preferably only 200 to 260nm. Moreover, for the development after the light irradiation, asolution mixture of a diethylene glycol, a morpholin, a monoethanolamine and pure water, or the like can be used.

As to the copolymers, a polymer having the excellent solvent resistancecan be synthesized without deteriorating the sensitivity for generatingthe photo decay by radically polymerizing a methyl methacrylate (MMA)and a methacrylic acid (MAA), or a methyl methacrylate (MMA) and amethacrylic anhydride (MAN) by a predetermined ratio, using a AIBN, orthe like as the polymerization initiator, and controlling the molecularweight and the dispersity to the optimum value. Therefor, it can be usedparticularly preferably in the present invention without generating thetrouble of dissolution, deformation, or the like at the time of applyinga liquid flow path forming material to be described later.

Moreover, since the PMMA based copolymer has a narrow sensitizing regionof 200 to 260 nm, and furthermore, the wavelength distribution of theexposing machine shown in FIG. 3 has the integrated value of the regionof about 1/10 compared with the integrated exposing amount at 270 to 330nm, it has only the sensitizing property of about ⅓ relatively comparedwith the sensitivity of the PMIPK. Therefore, if the two layers areexposed at the same time after the formation of the two layers, due tothe poor sensitivity of the upper layer (PMMA based copolymer), a shapewith the bulky upper side is provided, and furthermore, it is difficultto accurately form the lower layer pattern to be controlled. Therefore,as the configuration of the present invention, the materialconfiguration of the two layers (lower layer: PMIPK, upper layer: PMMAbased copolymer) is important, and at the same time, the process ofcarrying out the exposing and developing processes by the order from theupper layer to the lower layer, using an exposing machine with thewavelength selection for each. In the case the order is changed, adesired liquid flow path shape cannot be formed.

Furthermore, if the process of applying a mold member material to be theupper layer is carried out after patterning the lowermost layer formedon the substrate firstly, the upper layer surface follows the lowerlayer shape so as to have a wavy shape without being flattened, andfurthermore, the shape is uneven in the wafer. Therefore, it isdifficult to form a desired mold material height evenly.

From these results, the process of the present invention (process flow)is optimum for forming a flow path shape of the desired ink jetrecording head stably and accurately.

On the other hand, as the hardening composition having a negative typephotosensitive property as a nozzle forming material, those having theproperties as a member for forming a liquid flow path wall or adischarge port, and the resistance as the liquid flow path forming moldmaterial with respect to the process of dissolving and removing thepositive type resist, or the like may be used, and a photo settingcomposition including a cationically polymerizable chemical compound,cationic photopolymerization initiator, and a cationic polymerizationinhibitor can be used. As the cationically polymerizable chemicalcompound to be included in the photo setting composition, those capableof having the compounds coupled with each other, utilizing the cationicaddition polymerization reaction can be used. For example, as shown inthe Japanese Patent Application Laid-Open No. 3-143307 (corresponding toU.S. Pat. No. 5,478,606), epoxy compounds, which are solid at ordinarytemperature can be preferably used. For example, those having at leastabout 900 molecular weight out of the reaction products of a bisphenol Aand an epichlorohydrin, a reaction product of a phenol A including abromoth, and an epichlorohydrin, a phenol novolak, a reaction productsof an o-cresol novolak and epichlorohydrin, the polyfunctional epoxyresins having an oxycyclohexane skeleton disclosed in Japanese PatentApplication Laid-Open Nos. S60-161973, S62-221121, S64-9216, andH02-140219, or the like can be presented. They can be used by one kindor two or more kinds. Moreover, according to these epoxy compounds, acompound preferably having a 2,000 or less epoxy equivalent, and morepreferably having a 1,000 or less epoxy equivalent can be usedpreferably. If the epoxy equivalent is more than 2,000, the crosslinking density is lowered at the time of the hardening reaction so thatTg or the thermal deformation temperature of the hardened product islowered, or a problem may be generated in terms of the adhesion propertyand the ink resistance property.

As the cationic photopolymerization initiator, an aromatic iodoniumsalt, an aromatic sulfonium salt [see J. POLYMER SCI: Symposium No.56383-395 (1976)], and SP-150, SP-170, or the like, commerciallyavailable by Asahi Denka Co., Ltd., can be presented. Moreover, thecationic photopolymerization initiator can promote the cationic additionpolymerization reaction by using a reducing agent in a combination andheating (the cross linking density is improved compared with the singlecationic photopolymerization). However, in the case of using a cationicphotopolymerization initiator and a reducing agent in a combination, itis necessary to select the reducing agent so as to provide a so-calledredox type initiator system not to be reacted at an ordinary temperaturebut to be reacted at a certain temperature or more (preferably 60° C. ormore). As such a reducing agent, a copper compound, particularly inconsideration with the reactivity and solubility to an epoxy resin, acopper triflate (trifluoromethane copper sulfonate (II)) is optimum.Moreover, a reducing agent such as an ascorbic acid is also effective.Moreover, in the case a higher cross linking density (high Tg) such asincrease of the number of the nozzles (high speed printing property),and use of a non neutral ink (improvement of the water resistance of thecoloring agent) is necessary, the cross linking density can be raised bythe post process of soaking and heating the coating resin layer, usingthe above-mentioned reducing agent in a form of a solution after thedeveloping process of the above-mentioned coating resin layer to bedescribed later.

As needed, an additive, or the like can be added optionally to the photosetting type composition. For example, addition of a flexibilityproviding agent for the purpose of lowering the elastic modulus of anepoxy resin, addition of a silane coupling agent for the purpose ofobtaining the further adhesion force with respect to the substrate, orthe like can be presented.

After hardening the portions other than the portion with the lightblocking by the pattern exposure of the negative type resist layer via amask for blocking the light beam to the portion for providing thedischarge port, it is processed with a developing solution so as toremove the light blocking portion for forming the discharge port. Forthe pattern exposure, any type of the commonly used exposing devices maybe applied. It is preferably an exposing device for directing awavelength range coinciding with the absorbing wavelength range of thenegative type resist layer and not coinciding with the absorbingwavelength range of the positive type resist layer. Moreover, it ispreferable to carry out the development after the pattern exposure tothe negative type resist layer with an aromatic solvent, such as axylene.

In the present invention, it is preferable to form the first positivetype photosensitive material layer by forming a first positive typephotosensitive material layer by a solvent coating method, vaporizingthe coating solvent in the layer by heating, coating a material forforming the second positive type photosensitive material layer, andvaporizing the coating solvent by applying the heat to the formedcoating layer. Moreover, it is preferable that the glycol ether includedin the developing agent of the second positive type photosensitivematerial layer is at least one kind selected from the group consistingof an ethylene glycol monobutyl ether and a diethylene glycol monobutylether. On the other hand, it is preferable that the nitrogen containingbasic organic solvent included in the developing agent of the secondpositive type photosensitive material layer is at least one kindselected from the group consisting of an ethanol amine and a morpholin.Furthermore, it is preferable that the first wavelength range forsensitizing the first positive type photosensitive material is a rangeof 270 nm to 350 nm, and the second wavelength range for sensitizing thesecond positive type photosensitive material is a range of 230 nm to 260nm.

For the liquid discharge head according to the present invention, thosehaving a configuration with the liquid flow path height providedrelatively lower at a point adjacent to the bubble generating chamber onthe liquid discharge energy generating element, and those having aconfiguration with a dust scavenging pillar like member formed with thematerial comprising the liquid flow path provided in the liquid flowpath without reaching to the substrate, are preferable. Moreover, thosehaving a configuration with liquid supply ports connected commonly witheach liquid flow path formed in the substrate such that the liquid flowpath height at the central part of the liquid supply port is lower thanthe liquid flow path height at the opening rim part of the liquid supplyport are preferable. Moreover, those having a configuration with thecross-sectional shape of the bubble generating chamber on the liquiddischarge energy generating element of a convex shape are alsopreferable.

Next, the present invention will be explained in detail. According tothe production of the liquid discharge head by the present invention, itis advantageous in that the distance between the discharge energygenerating element (such as a heater) and the orifice (discharge port)and the positioning accuracy of the element and the orifice center, asthe one of the most important factors which influences the properties ofthe liquid discharge head can be set extremely easily, or the like. Thatis, according to the present invention, by controlling the coating filmthickness of the photosensitive material layer by two times, thedistance between the discharge energy generating element and the orificecan be set, and the coating film thickness of the photosensitivematerial layer can be controlled strictly with a good reproductivity bythe thin film coating technique, which has conventionally been used.Moreover, for the positioning of the discharge energy generating elementand the orifice, optical positioning by the photolithography process canbe enabled so that positioning can be carried out with a dramatic highaccuracy compared with the method of bonding the liquid flow pathstructure plate onto the substrate, which has conventionally been usedfor the production of the liquid discharge recording head.

Moreover, as the dissovable resist layer, a polymethyl isopropenylketone (PMIPK) is known. These positive type resists are a resist, whichhas the absorption peak in the vicinity of the 290 nm wavelength so thatthe two layer structure ink liquid flow path mold can be formed by thecombination with a resist having a photosensitive wavelength range,which is different from that of the resist.

On the other hand, a polymer compound comprising a copolymer of an estermethacrylate such as a polymethyl methacrylate (PMMA) and a methacrylicacid as one of the ionizing radiation decomposing type resists is apositive type resist having the sensitivity at the 250 nm or lesssensitive wavelength range. By applying the above-mentioned resist (PMMAbased copolymer) onto the above-mentioned resist (PMIPK), exposing thesame by a 230 to 260 nm band exposing wavelength range, and developingthe same with a GG-Developer (a liquid mixture of a diethylene glycol, amorpholin, a monoethanol amine and pure water) as the alkalinedeveloping solution, a PMMA based copolymer pattern can be formed ontothe PMIPK film. Then, by exposing the above-mentioned resist (PMIPK) bya 270 to 330 nm band exposing wavelength range, and developing the samewith a MIBK, or the like as the organic solvent, a two layer ink liquidflow path mold can be formed.

In the following, the process flow for forming the ink liquid flow pathaccording to the production method of the present invention will beexplained with reference to FIGS. 1A to 1F and 2.

FIGS. 1A to 1F show a process flow for forming a mold for an ink flowpath as a minute structure in the present invention, and FIGS. 2A to 2Hshow a nozzle forming process for an ink jet print head of the presentinvention.

First, FIGS. 1A to 1F will be explained. As shown in FIG. 1A, a positivetype resist layer 12 including a PMIPK is formed on a substrate 11. Acoating type resist having the PMIPK as the main component iscommercially available from Tokyo Ouka Kogyo Co., Ltd. as the productname: ODUR-1010. The coating film can be formed by a commonly used spincoat method. Next, as shown in FIG. 1B, a positive type resist layer 13(PMMA) including a PMMA based copolymer is formed on the positive typeresist layer 12 (ODUR) by the spin coat method.

Furthermore, as shown in FIG. 1C, the positive type resist layer 13(PMMA) including the PMMA based copolymer is exposed. For the positivetype resist layer (PMMA), a photo mask 16 for removing the exposed pointis adopted. At the time, by using a 230 to 260 nm band exposingwavelength range, the lower layer positive type resist can barely besensitized. This is derived from the fact that the absorption of theketone allows transmission of a 230 to 260 nm light beam mostly,deriving from the carbonyl group so as not to be sensitized. Bydeveloping the exposed positive type resist layer (PMMA) with a liquidmixture of a diethylene glycol, a morpholin, a monoethanol amine andpure water, a predetermined pattern is obtained. The above-mentioneddeveloping solution is alkaline. According to the developing solution,the dissolving rate of the acrylic based resist in the unexposed portionis extremely low, and furthermore, the influence to the lower layer canonly be slight at the time of developing the upper layer.

Then, as shown in FIG. 1D, by carrying out the post baking processincluding the substrate 11 at 100 to 130° C. for 3 minutes, aninclination of about 10° can be provided to the side wall of the upperlayer positive type resist. Then, as shown in FIG. 1E, the positive typeresist layer 12 (ODUR) including the PMIPK is exposed. For the positivetype resist layer (ODUR), a photo mask 17 for removing the exposed pointis adopted. At the time, by using a 270 to 330 nm band exposingwavelength range, the lower layer positive type resist can besensitized. Moreover, since the 270 to 330 nm range exposing wavelengthtransmits the upper layer positive type resist, it can hardly beinfluenced by the light beam coming around the mask or the reflectedlight beam from the substrate.

Then, as shown in FIG. 1F, by developing the exposed lower layerpositive type resist layer 12 (ODUR), a predetermined pattern isobtained. It is preferable to use a methyl isobutyl ketone as theorganic solvent for the developing solution. Since the unexposed PMMAbased copolymer is hardly dissolved by the developing solution, theupper layer pattern cannot be changed at the time of developing thelower layer resist.

Next, with reference to FIGS. 2A to 2H, the method for manufacturing aliquid discharge head of the present invention will be explained. InFIG. 2A, as the substrate 11, a silicon is used. That is, since thedriver, the logic circuit, or the like for controlling the dischargeenergy generating element 11 a are manufactured by a commonly usedsemiconductor production method, it is preferable to use a silicon forthe substrate. Moreover, as a method for forming a through hole forsupplying an ink to the substrate, it is also possible to use atechnique such as a YAG laser and sand blasting. However, it ispreferable that a through hole is not formed the substrate at the timeof applying a resist. As such a method, a silicon anisotropic etchingtechnique by an alkaline solution can be used. In this case, a maskpattern may be formed on the substrate rear surface with an alkalineresistant silicon nitride, or the like, and a membrane film to be theetching stopper may be formed on the substrate front surface with thesame material.

Next, as shown in FIG. 2B, a positive type resist layer 12 (ODUR)including a PMIPK is formed on the substrate. The coating film can beformed by a commonly used spin coating method. Next, as shown in FIG.2C, a positive type resist layer 13 (PMMA) including a PMMA basedcopolymer is formed on the positive type resist layer 12 (ODUR) by thespin coating method. Next, in order to obtain the structure shown inFIG. 2D, the positive type resist layer 13 (PMMA) including the PMMAbased copolymer is exposed. For the positive type resist layer (PMMA), aphoto mask (not shown) for removing the exposed point is adopted. thetime, by using a 23 p to 260 nm band exposing wavelength range, thelower layer positive type resist can barely be sensitized. This isderived from the fact that the absorption of the ketone allowstransmission of a 230 to 260 nm light beam mostly, deriving from thecarbonyl group so as not to be sensitized. By developing the exposedpositive type resist layer (PMMA) with a liquid mixture of a diethyleneglycol, a morpholin, a monoethanol amine and pure water, a predeterminedpattern is obtained. The above-mentioned developing solution isalkaline. According to the developing solution, the dissolving rate ofthe acrylic based resist in the unexposed portion is extremely low, andfurthermore, the influence to the lower layer can only be slight at thetime of developing the upper layer.

Then, in order to obtain the structure shown in FIG. 2E, the positivetype resist layer 12 (ODUR) including the PMIPK is exposed. For thepositive type resist layer (PDUR), a photo mask for removing the exposedpoint is adopted. At the time, by using a 270 to 330 nm band exposingwavelength range, the lower layer positive type resist can besensitized. Moreover, since the 270 to 330 nm range exposing wavelengthtransmits the upper layer positive type resist, it can hardly beinfluenced by the light beam coming around the mask or the reflectedlight beam from the substrate. Thereafter, by developing the exposedlower layer positive type resist layer (ODUR), a predetermined patternis obtained. It is preferable to use a methyl isobutyl ketone as theorganic solvent for the developing solution. Since the unexposed PMMAbased copolymer is hardly dissolved by the developing solution, theupper layer pattern cannot be changed at the time of developing thelower layer resist.

Next, as shown in FIG. 2F, a liquid flow path structure material 14 isapplied so as to cover the lower layer positive type resist layer 12 andthe upper layer positive type resist layer 13, a coating resin layer isprovided. For the applying operation, a commonly used solvent coatingmethod such as spin coating can be used. As it is shown in the U.S. Pat.No. 3,143,307, the liquid flow path structure material is a materialincluding as the main component an epoxy resin to be solid at anordinary temperature and an onium salt generating a cation by the lightirradiation, which has the negative type properties. Moreover, in thecase of forming a water-repellent material layer 14 a on the liquid flowpath structure material layer, as it is mentioned in Japanese PatentApplication Laid-Open No. 2000-326515, it can be carried out by forminga photosensitive water-repellent material layer, and exposing anddeveloping the same collectively. At the time, the photosensitivewater-repellent material layer can be formed by lamination. Thereafter,the liquid flow path structure material and the photosensitivewater-repellent material layer are exposed at the same time. Since theliquid flow path structure material 14 of the negative type propertiesis used in general, a photo mask 18 for preventing the light irradiationto the portion to be the discharge port is used. Then, by developing thecoating resin layer of the liquid flow path structure material, adischarge port 15 is formed. It is preferable to use an aromatic solventsuch as a xylene for the development.

Next, as shown in FIG. 2G, a cyclized isoprene 19 is applied on theliquid flow path structure material layer for protecting the materialfrom the alkaline solution. As the material, one commercially availableunder the name of OBC from the Tokyo Ouka Kogyo Co., Ltd. was used.Thereafter, by soaking the silicon substrate in a 22 wt % solution of atetramethyl ammonium hydride (TMAH) at 83° C. for 13 hours, a throughhole 20 for the ink supply was formed. Moreover, a silicon nitride usedas a mask and a membrane for the ink supply port formation ispreliminarily patterned on the silicon substrate.

Next, as shown in FIG. 2H, with the silicon substrate mounted in a dryetching device with the rear surface disposed upward after theanisotropic etching, the membrane film was removed by an etchant withoxygen mixed by 5% in CF4. Then, by soaking the above-mentioned siliconsubstrate in a xylene, the OBC was removed. Thereafter, by the entiresurface exposure, the positive type resist layers 12, 13 as the liquidflow path mold materials are decomposed. By directing a light beam of a330 nm or less wavelength, the upper layer and lower layer resistmaterials are decomposed to a low molecular compound so as to be easilyremoved by a solvent.

Finally, the positive type resist layer as the liquid flow path moldmaterial is removed by a solvent. According to the process, as shown inthe cross-sectional view of FIG. 2H, a liquid flow path 21 communicatingwith the discharge port 15 can be formed. The liquid flow path 21 of thepresent invention has a shape with the liquid flow path height lower inthe vicinity of the discharge chamber as a bubble generating chamber,forming a part of the liquid flow path and in contact with a heater(liquid discharge energy generating part). By applying the vibration ofan ultrasonic wave, a mega sonic, or the like, in the mold materialremoving process with a solvent, the dissolving and removing time can bemade shorter.

Here, in FIG. 3, a schematic diagram of the optical system of aproximity exposing device used as a commonly used exposing device isshown. It has a configuration of reflecting an ultraviolet ray or a farultraviolet ray generated from a high pressure mercury lamp (2.0 kW,Xe—Hg lamp) 100 to a screen 104 by a reflected light collecting device100, selecting a light beam of a desired wavelength by a cold mirror 101for reflecting only the light beam of a wavelength necessary for theresist exposure, enlarging and evening with a fly eye lens 102, anddirecting the light beam to a resist (not shown) via a condenser lens105, a projection optical system and a mask 106. In the case all thelight beams are reflected, the light beams of a wavelength unnecessaryfor the sensitization of the resist are converted to heat so as toprevent the deterioration of the patterning accuracy. According to amask aligner UX-3000SC manufactured by Ushio Inc., a cut filter forblocking the light beams of the wavelengths other than desired one isprovided automatically detachably between the above-mentioned fly eyelens 102 and the cold mirror. Accordingly, by exposing and patterningthe two kinds of the different resists, using the exposing wavelengthsof two kinds of the different wavelength ranges, an ink jet head havingthe ink liquid flow path height provided partially differently can bemanufactured by the production flow shown in FIGS. 1A to 1F and 2A to2H.

FIGS. 4A to 4G and FIGS. 5A to 5D show the most preferable process flowusing the PMMA based copolymer positive type resist as the upper layerresist. FIGS. 5A to 5D shows the subsequent steps of the process shownin FIGS. 4A to 4G. In FIG. 4A, a positive type resist layer 32 includinga PMIPK is applied on a substrate 31 and baked. For the application, acommonly used solvent coat method such as spin coating and bar coatingcan be used. Moreover, the baking temperature is preferably 100 to 150°C. Then, as shown in FIG. 4B, a photo decay type positive type resist 33of a PMMA based copolymer is applied as the upper layer of the positivetype resist layer 32 including the PMIPK and baked. For the application,commonly used solvent coat method such as spin coating and bar coatingcan be used. Moreover, the baking temperature is preferably 100 to 150°C. Then, as shown in FIG. 4C, the photo decay type positive type resistlayer 33 of the PMMA based copolymer is exposed using an exposingwavelength of a 230 to 260 nm band. For example, by blocking the lightbeams of 260 nm or more using the mask aligner UX-3000SC manufactured byUshio Inc., a desired exposing wavelength of a 230 to 260 nm band can bedirected selectively.

Then, as shown in FIG. 4D, the upper layer resist layer 33 is developed.As the developing solution, a solvent capable of at least dissolving theexposing part and hardly dissolving the unexposed part can be used. As aresult of the elaborate discussion of the present inventors, it wasfound out that a developing solution containing a glycol ether having 6or more carbon atoms to be mixed with water by an optional ratio, anitrogen containing basic organic solvent and water can be usedparticularly preferably. As the glycol ether, an ethylene glycolmonobutyl ether and/or diethylene glycol monobutyl ether, and as thenitrogen containing basic organic solvent, an ethanolamine and/ormorpholine are particularly preferred. For example, as a developingsolution for the PMMA (polymethyl methacrylate) used as a resist in theX ray lithography, a developing solution having the compositiondisclosed in Japanese Patent Application Laid-Open No. H03-10089(corresponding to U.S. Pat. No. 4,393,129) can be used preferably alsoin the present invention. As to the composition ratio of each of theabove-mentioned components, for example, a developing solutioncontaining:

-   Diethylene glycol monobutyl ether 60 vol %-   Ethanolamine: 5 vol %-   Morpholin: 20 vol %-   Ion exchange water: 15 vol %    can be used.

Furthermore, as shown in FIG. 4E, the lower layer positive type resistlayer 32 is exposed. For the exposure, it is exposed using an exposingwavelength of a 270 to 330 nm band. For example, by blocking the lightbeams of 270 nm or less using the mask aligner UX-3000SC manufactured byUshio Inc., a desired exposing wavelength of a 270 to 330 nm band can bedirected selectively.

Then, as shown in FIG. 4F, the positive type resist layer 32 isdeveloped. For the development, it is preferable to use a methylisobutyl ketone as the developing solution for the PIMPK, however, anyorganic solvent capable of dissolving the exposed part of the PIMPKwithout dissolving the unexposed part can be used. Then, as shown inFIG. 4G, a liquid flow path structure material 34 is applied so as tocover the lower layer positive type resist layer 32 and the upper layerpositive type resist layer 33. For the application, a commonly usedsolvent coat method such as spin coating can be used. As it is shown inthe U.S. Pat. No. 3,143,307, the liquid flow path structure material isa material including as the main component an epoxy resin to be solid atan ordinary temperature and an onium salt generating a cation by thelight irradiation, which has the negative type properties. FIG. 5A showsthe process of carrying out the light irradiation to the liquid flowpath structure material, using a photo mask 38 without directing a lightbeam to a portion to be the ink discharge port. Next, as shown in FIG.5B, the pattern development of the ink discharge port 35 is carried outfor the photosensitive liquid flow path structure material 34.

For the pattern exposure, any of the commonly used exposing devices canbe used. It is preferable to develop the photosensitive liquid flow pathstructure material with an aromatic solvent not dissolving the PMIPK,such as a xylene. Moreover, in the case of forming a water-repellentmaterial layer on the liquid flow path structure material layer, as itis mentioned in Japanese Patent Application Laid-Open No. 2000-326515,it be carried out by forming a photosensitive water-repellent materiallayer, and exposing and developing the same collectively. At the time,the photosensitive water-repellent material layer can be formed bylamination. Then, as shown in FIGS. 5A to 5D, an ionizing radiation of300 nm or less is directed correctively beyond the liquid flow pathstructure material layer. This is for the purpose of decomposing thePMIPK and the PMMA copolymer resist so as to be a low molecule forfacilitating the removal.

Finally, the positive type resists 32, 33 used for the mold are removedby a solvent. Thereby, a liquid flow path 39 including a dischargechamber is formed as shown in FIG. 5D.

By using the processed as mentioned above, the height of the ink liquidflow path from the ink supply port to the heater can be changed.

According to the production method, the height of the ink liquid flowpath from the ink supply port to the heater can be changed. Optimizationof the ink liquid flow path shape from the ink supply port to thedischarge chamber not only relates significantly to the ink refillingrate to the discharge chamber but also enables reduction of the crosstalk between the discharge chambers. The specification of the U.S. Pat.No. 4,882,595 by Trueba, et al. discloses the relationship between thetwo-dimensional shape, that is, the shape in the direction parallel tothe substrate, of the ink liquid flow path to be formed by thephotosensitive resist on the substrate and the above-mentionedproperties. On the other hand, according to Japanese Patent ApplicationLaid-Open No. H10-291317 by Mercy et al., it is disclosed that a resinliquid flow path structure plate is processed in a three-dimensionaldirection in the in-plane direction and the height direction withrespect to the substrate by an excimer laser so as to change the heightof the ink liquid flow path.

However, in the case of the process by an excimer laser, due to theexpansion of the film by the heat at the time of process, or the like, asufficient accuracy cannot be realized in most cases. In particular, theprocess accuracy in the depth direction of the resin film by the excimerlaser is influenced by the laser irradiation distribution and the laserbeam stability so that the accuracy capable of clarifying theinteraction between the ink liquid flow path shape and the dischargeproperties cannot be ensured. Therefore, according to Japanese PatentApplication Laid-Open No. H10-291317, a clear relationship between theink liquid flow path height shape and the discharge properties is notmentioned.

According to the production method of the present invention, it isexecuted by a solvent coat method used as the semiconductor productiontechnique such as spin coating, the height of the ink liquid flow pathcan be formed stably with an extremely high accuracy. Moreover, as tothe two-dimensional shape in the direction parallel to the substrate,since the semiconductor photolithography technique is used, the submicron accuracy can be realized.

Next, the structure of an ink jet head capable of using the presentinvention will be explained with reference to FIGS. 6A to 6B. FIG. 6A isa vertical cross-sectional view showing the nozzle structure of an inkjet head with the discharge chamber improved by the production method ofthe present invention, and FIG. 6B is a vertical cross-sectional viewshowing the nozzle structure for the comparison with the head shown inFIG. 6A. As shown in FIG. 6A, the head using the present invention ischaracterized in that the discharge port shape of the discharge chamber77 has a convex cross-sectional shape. The ink discharge energy ischanged drastically by the ink flow resistance defined by the dischargeport shape in the heater upper part. According to the conventionalproduction method, since the discharge port shape is formed bypatterning the liquid flow path structure material, it is a shape withthe discharge port pattern formed in the mask projected thereto.Therefore, principally, the discharge port is formed through the liquidflow path structure material layer by the same area as the dischargeport opening area in the liquid flow path structure material surface.However, according to the production method of the present invention, bychanging the pattern shapes of the lower layer material and the upperlayer material, the discharge port shape of the discharge chamber 77 canbe formed in a convex shape. Thereby, the effects of making the inkdischarge rate higher and increasing the straight movement property ofthe ink can be provided so that a recording head capable of recordingwith a higher image quality can be provided.

Hereinafter, with reference to the drawings as needed, the presentinvention will be explained in detail.

First Embodiment

In each of FIGS. 7A to 7H, an example of the production procedure of aliquid discharge head according to the present invention is shown. FIG.7I is a schematic cross-sectional view of a liquid discharge headcompleted by the production method shown in FIGS. 7A to 7H.

Although a liquid jetting recording head having two orifices (dischargeports) is shown in this embodiment, of course it is needless to say thatthe same is applied to the case of a high density multi array liquidjetting recording head having more orifices. First, in this embodiment,for example as shown in FIG. 7A, a substrate 201 made of a glass,ceramics, a plastic, a metal, or the like can be used. FIG. 7A is aschematic perspective view of the substrate before the photosensitivematerial layer formation. The substrate 201 functions as a part of thewall member of the liquid flow path, and as long as it can function as asupporting member for a liquid flow path structure member comprising aphotosensitive material layer to be described later, it can be usedwithout limitation of the shape, the material, or the like. On theabove-mentioned substrate 201, a desired number of liquid dischargeenergy generating elements 202 such as an electro thermal conversionelement, a piezoelectric element, or the like are disposed (an exampleof two pieces is shown in FIG. 7A). By providing the discharge energyfor discharging recording liquid small droplets to the ink liquid by theliquid discharge energy generating elements 202, a recording operationis carried out. For example, in the case an electro thermal conversionelement is used as the liquid discharge energy generating elements 202,by heating the recording liquid in the vicinity by the elements, thedischarge energy is generated. Moreover, for example, in the case apiezoelectric element is used, by the mechanical vibration of theelements, the discharge energy is generated.

These elements 202 are connected with a control signal inputtingelectrode (not shown) for operating these elements. Moreover, althoughvarious functional layers such as a protection layer are provided ingeneral, for the purpose of the improvement of the use endurance ofthese discharge energy generating elements 202, of course, also in thepresent invention, there is no problem to provide such a functionallayer. Most commonly, a silicon is used for the substrate 201. That is,since the driver, the logic circuit, or the like for controlling thedischarge energy generating element are manufactured by a commonly usedsemiconductor production method, it is preferable to use a silicon forthe substrate. Moreover, as a method for forming a through hole forsupplying ink to the substrate, it is also possible to use a techniquesuch as a YAG laser or sand blasting. However, it is preferable that athrough hole is not formed in the substrate at the time of applying aresist. As such a method, a silicon anisotropic etching technique by analkaline solution can be used. In this case, a mask pattern may beformed on the substrate rear surface with an alkaline resistant siliconnitride, or the like, and a membrane film to be the etching stopper maybe formed on the substrate front surface with the same material.

Then, as shown in FIG. 7B, a PMIPK positive type resist layer 203 isapplied onto the substrate 201 including the liquid discharge energygenerating elements 202. As to the PMIPK, ODUR-1010 commerciallyavailable from the Tokyo Ouka Kogyo Co., Ltd. was adjusted so as to havethe resin concentration to 20 WT % and used. The pre baking operationwas carried out by a hot plate at 120° C. for 3 minutes. Furthermore, ina nitrogen atmosphere, a heat treatment was carried out at 150° C. for60 minutes in an oven. The film thickness of the coating film was 15 μm.

Then, as shown in FIG. 7C, a photo decay type positive type resist layer204 of a PMMA copolymer was applied on the above-mentioned positive typeresist layer 203. As the photo decay type positive type resist of a PMMAcopolymer, the following positive resist was used.

-   Radical polymerization product of a methyl methacrylate and a    methacrylic acid (PMMA based copolymer)-   Weight average molecular weight (Mw: based on the    polystyrene)=170,000-   Dispersity (Mw/Mn)=2.3

The resin powders were dissolved in a diglyme solvent by about a 25 wt %solid component concentration, and used as the resist liquid. Theviscosity of the resist solution at the time was about 600 cps. Afterapplying the resist liquid by the spin coating method and pre baking at100° C. for 3 minutes, a heat treatment was out at 150° C. for 30minutes in a nitrogen atmosphere by an oven. The film thickness of theresist layer after the heat treatment was 5 μm. Then, as shown in FIG.7D, the photo decay type positive type resist layer 204 of a PMMAcopolymer of a carboxylic acid was exposed. As to the exposing device,the mask aligner UX-3000SC manufactured by Ushio Inc. was used, and anexposing wavelength of a 230 to 260 nm band was directed selectively.

Then, as shown in FIG. 7E, the photo decay type positive type resistlayer 204 of a PMMA copolymer was developed. For the development, bydeveloping the same with a developing solution of the followingcomposition, a desired pattern was formed.

-   Developing solution-   Diethylene glycol monobutyl ether: 60 vol %-   Ethanol amine: 5 vol %-   Morpholin: 20 vol %-   Ion exchange water: 15 vol %

Then, as shown in FIG. 7F, the lower layer PMIPK positive type resistlayer 203 was patterned (exposure, development). As the exposing device,the same device was used, and using a cut filter, a 270 to 330 nm bandexposing wavelength was directed selectively. The development wascarried out with a methyl isobutyl ketone.

Then, as shown in FIG. 7G, a liquid flow path structure material 207layer was formed so as to cover the patterned lower layer positive typeresist layer 203 and the upper layer positive type resist layer 204. Thelayer material was manufactured by dissolving 50 parts of EHPE-3150commercially available from Daicel Chemical Industries, Ltd., 1 part ofa photo cationic polymerization initiator SP-172 commercially availablefrom Asahi Denka Co., Ltd., and 2.5 parts of a silane coupling materialA-187 commercially available from Nihonunica Corporation in 50 parts ofa xylene used as a coating solvent. The coating operation was carriedout by spin coating, and the pre baking operation was carried out on ahot plate at 90° C. for 3 minutes. For the exposure, a mask alignerMPA-600FA manufactured by Canon was used, and the exposure was carriedout by 3 J/cm2. The development was carried out by soaking the same in axylene for 60 seconds. Thereafter, by baking at 100° C. for 1 hour, theadhesion of the liquid flow path structure material was improved.

Then, pattern exposure and development of the ink discharge port 209 iscarried out for the liquid flow path structure material 207. For thepattern exposure, any of the commonly used exposing devices can be used.Although it is not shown in the figure, a mask for preventing the lightirradiation was used for a portion to be the ink discharge port at thetime of the exposure. Thereafter, although it is not shown in thefigure, a cyclized isoprene was applied on the liquid flow pathstructure material layer for protecting the material from the alkalinesolution. As the material, one commercially available under the name ofOBC from the Tokyo Ouka Kogyo Co., Ltd. was used. Thereafter, by soakingthe silicon substrate in a 22 wt % solution of a tetramethyl ammoniumhydride (TMAH) at 83° C. for 13 hours, a through hole (not shown) forthe ink supply was formed. Moreover, a silicon nitride used as a maskand a membrane for the ink supply port formation is preliminarilypatterned on the silicon substrate. With the silicon substrate mountedin a dry etching device with the rear side disposed upward after theanisotropic etching, the membrane film was removed by an etchant withoxygen mixed by 5% in CF4. Then, by soaking the above-mentioned siliconsubstrate in a xylene, the OBC was removed.

Then, as shown in FIG. 7H, an ionizing radiation 208 of 300 nm or lesswas directed to the entire surface of the liquid flow path structurematerial 207 using a low pressure mercury lamp so as to decompose theupper layer positive type resist of a PMIPK and the lower layer positivetype resist of a PMMA based copolymer. The exposing amount is 50 J/cm2.

Thereafter, by soaking the substrate 201 in a methyl lactate, the moldresist was removed collectively. At the time, by placing the same in a200 MHz megasonic vessel, the elution time was shortened. Thereby, anink liquid flow path 211 including the discharge chamber was formed soas to manufacture an ink discharge element (see FIG. 7I) of a structurefor guiding an ink from the ink supply port 210 to each dischargechamber via each ink liquid flow path 211 and for discharging ink fromdischarge port 209.

The discharge element manufactured accordingly was mounted in the inkjet head unit of the form shown in FIGS. 9A and 9B for carrying out thedischarge and recording evaluation so as to find that a preferable imagerecording can be carried out. As to the form of the above-mentioned inkjet head unit, as shown in FIGS. 9A to 9B, for example, a TAB film 214for providing and receiving a recording signal with the recording devicemain body is provided on the outer surface of a supporting member forsupporting an ink tank 213 detachably, and an ink discharge element 212is connected with an electric wiring via an electric connection lead 215on the TAB film 214.

Modified Embodiment

According to the first embodiment, an ink jet head of the structureshown in FIG. 6A was manufactured. According to this embodiment, asshown in FIG. 9A, a discharge chamber 77 has a rectangular part formedwith the lower layer resist of a 25 μm square and a 10 μm height, arectangular part formed with the upper resist of a 20 μm square and a 10μm height, and a discharge port of a 15 μm diameter round hole. Thedistance form the heater 73 to the opening surface of the discharge portis 26 μm. FIG. 9B shows the cross-sectional shape of the discharge portof the head by the conventional production method. The discharge chamber77 is rectangular with a 20 μm side and a 20 μm height. The dischargeport 72 is formed as a 15 μm diameter round hole. According to thecomparison of the discharge properties of each of the heads of the FIGS.9A to 9B, the head shown in FIG. 9A has the discharge rate of 15 m/secby a 3 ng discharge amount, and the impact accuracy at a position awayfrom the discharge port 74 in the discharge direction by 1 mm was 3 μm.Moreover, the head shown in FIG. 9B has the discharge rate of 9 m/sec bya 3 ng discharge amount, and the impact accuracy was 5 μm.

EXAMPLES

In order to examine the effects of the present invention, a head wasmanufactured and evaluated in the same way as it is mentioned in thefirst embodiment except that the following mold material formingmaterial was used in the conditions shown in the table 1 in a form of acolor head mounted in an IJ printer (PIXUS 560i) manufactured by Canon.

The mold material forming material used in the example 1 and thecomparative examples 1, 2 was PMIPK and P(MMA-MAA). As to the PMIPK,ODUR-1010 commercially available by the Tokyo Ouka Kogyo Co., Ltd. wasadjusted so as to have the resin concentration to 20 WT % and used. Asto the P(MMA-MAA), resin powders synthesized so as to provide a radicalpolymerization product of a methyl methacrylate and a methacrylic acid(PMMA based copolymer), weight average molecular weight (Mw: based onthe polystyrene)=170,000, dispersity (Mw/Mn)=2.3, dissolved in a diglymesolvent by about a 30 wt % solid component concentration, was used as aresist liquid 1, and resin powders synthesized so as to provide aradical polymerization product of a methyl methacrylate and amethacrylic acid (PMMA based copolymer), weight average molecular weight(Mw: based on the polystyrene)=30,000, dispersity (Mw/Mn)=2.1, dissolvedin a diglyme solvent by about a 25 wt % solid component concentration,was used as a resist liquid 2.

Moreover, the mold material forming material used in the example 2 andthe comparative example 3 was PMIPK and P(MMA-MAN). As to the PMIPK,ODUR-1010 commercially available by the Tokyo Ouka. Kogyo Co., Ltd. wasadjusted so as to have the resin concentration to 20 WT % and used. Asto the P(MMA-MAN), resin powders synthesized so as to provide a radicalpolymerization product of a methyl methacrylate and a methacrylicanhydride (PMMA based copolymer), weight average molecular weight (Mw:based on the polystyrene)=30,000, dispersity (Mw/Mn)=3.4, dissolved in acyclohexanone solvent by about a 25 wt % solid component concentration,was used as a resist liquid.

As to the evaluation, cracking was judged by the generation ratio by thenumber of defect chips (M pieces) with the crack generation with respectto the number of the chips to be provided in a used wafer size (Npieces). As to the defect evaluation, with even one point in each chip,it judged as a defect goods.

The judging criteria were as follows:◯:(M/N)*100>90%Δ:(M/N)*100<70%

Moreover, as to the residue, in the same manner, it was judged by thegeneration ratio. As to the nozzle yield, the value of (M/N)×100 of thenumber of the manufactured chips (M pieces) without cracking or residuewith respect to the total number of the pieces (N pieces) in the usedwafer size is shown. As to the printing yield, the value of (m/n)×100 ofthe number of the heads (m pieces) within 5 μm in terms of theunevenness value σ in a printing test by the printer with respect to thenumber of heads (n pieces) assembled as a head.

As it is apparent from the table 1 showing the results, according to theIJ heads manufactured by the configuration of the present invention, inboth the upper layer and the lower layer, no film reduction, cracking orresidue was found in the mold material, and both the nozzle yield andthe printing yield were preferable.

On the other hand, according to the comparative examples 1, 3manufactured by thermal cross linking, sensitivity deterioration andcracking were observed in the lower layer mold material with the thermalcross linking carried out, and furthermore, residue was observed. Then,in terms of both the nozzle yield and the printing yield, they werepoorer than those manufactured by the configuration of the presentinvention. According to the comparative example 2, owing to the absenceof the thermal cross linking, even though cracking, residue, or the likewas not observed, film reduction was observed in the upper layer moldmaterial, and furthermore, both the nozzle yield and the printing yield,they were drastically poorer than those manufactured by theconfiguration of the present invention.

The printing failure generated in the IJ heads manufactured by theconfiguration of the present invention was mainly the phenomenon withoutjumping the ink droplets from a part of the nozzles (it is referred toas the non discharge phenomenon) derived from dusts, or the like,introduced at the time of the head assembly (at the time of mounting).From the results, it is learned that in order to provide an inexpensiveand highly reliable ink jet recording head, formation based on theproduction method of the present invention is preferable.

This application claims priority from Japanese Patent Application No.2004-190481 filed Jun. 28, 2004, which is hereby incorporated byreference herein.

TABLE Lower layer mold material Upper layer mold material Removingproperty Film Film Irra- Print- thick- Sensi- Crack- thick- Sensi- FilmCrack- diation Removal Nozzle ing Material ness tivity ing Material nesstivity loss ing amount time Residue yield yield Example 1 PMIPK*¹ 18 μM20 J None P(MMA- 5 μM 6 J None None 51 J 90 min. None 95% 96% MMA)*²Comparative P(MMA- 18 μM 50 J Δ PMIPK*⁴ 5 μM 8 J None None 270 J  180min.  Present 65% 60% Example 1 MAA)*³ Comparative PMIPK*¹ 18 μM 20 JNone P(MMA- 5 μM 5 J x (50%) None 51 J 90 min. None 30% 20% Example 2MAA)*⁵ Example 2 PMIPK*⁶ 15 μM 18 J None P(MMA- 5 μM 6 J None None 51 J90 min. None 94% 97% MAA)*⁷ Comparative P(MMA- 15 μM 50 J Δ PMIPK*⁹ 5 μM8 J None None 270 J  180 min.  Present 68% 66% Example 3 MAA)*⁸ *¹Forthe PMIPK, a film was formed by pre baking (120° C., 3 minutes) afterthe application, and curing (150° C., 6 minutes). *²For the (P(MMA-MAA):molecular weight: 170,000}, a film was formed by pre, baking (100° C., 3minutes) after the application, and curing (150° C.₁ 6 minutes). *³Forthe (P(MMA-MAA): molecular weight: 30,000}, a film was formed by prebaking (100° C., 3 minutes) after the application, and curing (250° C.,1 hour). *⁴For the PIMPK, a film was formed by pre baking (120° C., 3minutes) after the application. *⁵For the (P(MMA-MAA): molecular weight:30,000}, a film was formed by pre baking (100° C., 3 minutes) after theapplication. *⁶For the PMIPK, a film was formed by pre baking (120′ C, 3minutes) after the application, and curing (150° C., 6 minutes). *⁷Forthe P(MMA-MAN), a film was formed by pre baking (100° C., 3 minutes)after the application, and curing (150° C., 6 minutes). *⁸For theP(MMA-MAN), a film was formed by pre baking (100° C., 3 minutes) afterthe application, and curing (250° C., 1 hour). *⁹For the PIMPK, a filmwas formed by pre baking (120° C., 3 minutes) after the application.

1. A method for manufacturing a liquid discharge head comprising apassage for a liquid, which communicates with a discharge port fordischarging the liquid, on a substrate with a liquid discharge energygenerating element for generating energy used for discharging theliquid, the method comprising: providing a first layer including apolymethyl isopropenyl ketone on the substrate; providing, on the firstlayer, a second layer including a photosensitive material of a copolymerobtained by copolymerization of a methacrylate and a methacrylic acid,with a weight average molecular weight of the copolymer of 50,000 to300,000 and a ratio of the methacrylic acid included in the copolymer of5 to 30% by weight, where the second layer on the first layer is bakedat a temperature of 100 to 150° C.; forming a second part of a mold ofthe passage from the second layer by exposing a part of the secondlayer, and removing an exposed part of the second layer using adeveloping solution; forming a first part of the mold of the passagefrom the first layer by exposing a part of the first layer, and removingan exposed part of the first layer using a developing solution;providing a coating layer to coat the mold; and removing the mold toform the passage.
 2. The method for manufacturing a liquid dischargehead according to claim 1, wherein a first wavelength of light used toexpose the first layer is in a 270 nm to 350 nm range, and a secondwavelength of light used to expose the second layer is in a 230 nm to260 nm range.
 3. A method for manufacturing a liquid discharge headcomprising a passage of a liquid, which communicates with a dischargeport for discharging the liquid, on a substrate with a liquid dischargeenergy generating element for generating energy used for discharging theliquid, the method comprising: providing a first including a polymethylisopropenyl ketone on the substrate; providing, on the first layer, asecond layer including a photosensitive material of a copolymer obtainedby copolymerization of a methacrylate and a methacrylic anhydride, witha weight average molecular weight of the copolymer of 10,000 to 100,000and a ratio of the methacrylic anhydride included in the copolymer of 5to 30% by weight, where the second layer on the first layer is baked ata temperature of 100 to 150° C.; forming a second part of a mold of thepassage from the second layer by exposing a part of the second layer,and removing an exposed part of the second layer using a developingsolution; forming a first part of the mold of the passage from the firstlayer by exposing a part of the first layer, and removing an exposedpart of the first layer using a developing solution; providing a coatinglayer to coat the mold; and removing the mold to form the passage. 4.The method for manufacturing a liquid discharge head according to claim3, wherein a first wavelength of light used to expose the first layer isin a 270 nm to 350 nm range, and a second wavelength of light used toexpose the second layer is in a 230 nm to 260 nm range.